The Government is offering to change controversial proposals to drop limits on lobby-group spending during election campaigns.

Justice Minister Simon Power has proposed removing most controls on parallel campaigns by lobby groups during elections, while retaining restrictions on political parties.

Power confirmed in Parliament yesterday that under legislation being drafted to replace the repealed Electoral Finance Act, parallel campaigners would not face restrictions on spending or what they said during campaigns.

Power said the requirement that lobbyists register with the Electoral Commission if they spent more than $12,000 would ensure the system was open and transparent.

However, after an outcry from Labour and the Greens, Power said he was prepared to revisit the proposal if a select committee could agree on a suitable alternative.

He also announced that lobbyists running supportive campaigns for a party would have to seek the party's consent, and they would count towards that party's spending limit.

Earlier, his office had insisted that positive campaigning would not count towards party spending limits.

Labour has agreed to vote for Power's bill as far as a select committee. However, justice spokeswoman Lianne Dalziel said she had grave concerns about the removal of spending restrictions on parallel campaigns.

She said she feared parties could be allowed to give money to lobbyists to run campaigns on their behalf and avoid their spending cap.

Dalziel said it was also essential that parallel campaigners be forced to disclose how much money they spent.

She said Labour was open to increasing the $120,000 limit on parallel campaigns as long as there was a cap.

In Parliament, Greens co-leader Metiria Turei quoted the Royal Commission on Electoral Reform, which said in 1986 that limiting spending by political parties but not third-party interests was "illogical" and unfair.

Turei said there was nothing in the Government's proposals that would prevent a political party from giving money to a lobbyist to run a supportive and uncapped campaign.